When to request immunofluorescence: practical hints.

This review highlights important considerations in obtaining good skin biopsy specimens to optimize results of direct immunofluorescence (IF) studies and also summarizes the various patterns of cutaneous IF deposition and their associated diagnoses. IF findings of immunobullous diseases, lupus erythematosus, vasculitis, lichen planus, and erythema multiforme are included. The uses of indirect IF studies are also reviewed including newer modifications that are valuable in helping to diagnose epidermolysis bullosa acquisita and paraneoplastic pemphigus.